NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
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ID: nht92-9.55OpenDATE: January 9, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: John H. Heinrich -- District Director of Customs, U.S. Customs Service TITLE: Case No. 92-2704-00015 ATTACHMT: Attached to letter dated 12/05/91 from John H. Heinrich and Kathleen M. Tobin to the Office of Chief Counsel, DOT (OCC 6758) TEXT: This responds to your letter of December 5, 1991, enclosing a petition for relief from the forfeiture of "200 Spinner Wheel Nuts" seized by the Customs Service as violative of 49 CFR Sec. 571.211. The petitioner expresses the opinion that the wheel nuts should be exempt from DOT regulations, stressing safety considerations and the need to replace worn parts on vehicles manufactured in the 1950's. You have also enclosed a copy of the petitioner's own parts list that identifies the wheel nuts as part of a conversion kit, intended to replace disc wheels with wire wheels. Federal Motor Vehicle Safety Standard No. 211, Wheel Nuts, Wheel Discs, and Hub Caps, 49 CFR 571.211, precludes, for use on passenger cars, wheel nuts that incorporate winged projections. The chrome wheel nuts depicted in the Moss Motors catalogue page which you enclosed (Parts Nos. 200-210 and 200-220) clearly incorporate winged projections, and are the type of wheel nuts that Standard No. 211 addresses and prohibits. As such, they may not be imported for sale in the United States. We have discounted petitioner's safety arguments. This is the first allegation in the nearly 24 years that the standard has been in effect that the spinners are required to replace original equipment, implying that there is no acceptable substitute that would conform with Standard No. 211. In our view, no justification has been shown for granting the petition. |
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ID: 77-4.26OpenTYPE: INTERPRETATION-NHTSA DATE: 11/03/77 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr; NHTSA TO: American Trailers, Inc. TITLE: FMVSS INTERPRETATION TEXT: This responds to your July 20, 1977, letter asking whether your certification labels comply with Part 567, Certification, and Standard No. 120, Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars. As stated to you in an earlier letter, the National Highway Traffic Safety Administration does not issue approvals of compliance with Federal safety standards or regulations. The agency will, however, give you an informal opinion as to whether your labels appear to comply with the requirements. The agency has determined that the two labels that you submitted do not follow the format established in the regulations and, therefore, do not comply with the requirements. If "R" denotes radial ply and "F" denotes load range, the tire designation should be 10.00 R 20 (F). SINCERELY, American Trailers, Inc. July 20, 1977 Roger Tilton Office of the Chief Counsel National Highway Traffic Safety Admin. SUBJECT: NOA-30 (RST) This letter is to confirm our telephone conversation of July 19, concerning Mr. Levin's letter of July 13, 1977. We are enclosing two new samples certification labels which have been modified from the original as submitted May 25, 1977. It is our understanding that the changes in the wording for the tire and rim size, and the deletion of the wording "maximum with minimum size tire-rims shown below" will give apparent compliance with the requirements of Part 567 and Standard No. 120. Jerry McNeil Director of Engineering ENCLS. |
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ID: 77-4.34OpenTYPE: INTERPRETATION-NHTSA DATE: 11/10/77 FROM: AUTHOR UNAVAILABLE; J. J. Levin, Jr.; NHTSA TO: Indiana Mills and Manufacturing, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your letter of October 4, 1977, to Mr. Francis Armstrong of our Office of Standards Enforcement, in which you asked whether our regulations require seat belts in fifth wheel vehicles. Our seat belt requirements are specified in Federal Motor Vehicle Safety Standard No. 208 (49 CFR 571.208), which applies to passenger cars, multipurpose passenger vehicles, trucks and buses. I am assuming that by fifth wheel vehicle you mean a towed vehicle attached to the towing vehicle by means of a fifth wheel. If I am correct in this assumption, these vehicles would be classified as trailers, which are not subject to Standard No. 208. There would therefore be no Federal requirement for seat belts in these vehicles. SINCERELY, October 4, 1977 Francis Armstrong, Director Office of Standards Enforcements Motor Vehicle Programs National Highway Traffic Safety Administration To further promote the R.V. industry, the Pennsylvania Recreational Vehicle and Camping Association (PRVCA) supported fifth-wheel riding, provided certain safety features were incorported. Now, fifth wheel riding has been made part of the Pennsylvania Vehicle code, becoming legal July 1, 1977. This brings to 25 the number of states that have made it legal to ride in fifth wheels. The law requires seat belts in all designated seating. Would you please advise me as to how the code speaks to the use of seat belts in fifth wheel vehicles. Thank you for your assistance. Robert W. Locke Manager RV Sales -- INDIANA MILLS AND MANUFACTURING, INC. |
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ID: nht75-6.38OpenDATE: 10/10/75 FROM: WILLIAM T. COLEMAN -- SECRETARY OF TRANSPORTATION TO: HONORABLE BARBER B. CONABLE -- HOUSE OF REPRESENTATIVES TITLE: NONE ATTACHMT: LETTER DATED SEPTEMBER 5, 1975 FROM BARBER CONABLE TO HON. WILLIAM T. COLEMAN; LETTER DATED AUGUST 7, 1975 FROM F. J. GUPPENBERGER TO REP. BARBER CONABLE TEXT: This is in response to your letter of September 5, 1975, requesting information concerning an inquiry from one of your constituents, Mr. F. J. Guppenberger, relating to the permissibility of raising cars' rear bumpers. Motor Vehicle Safety Standard No. 215, Exterior Protection, imposes performance requirements on automobile bumper systems. One of these requirements specifies impacts at certain heights, and has the effect of requiring bumpers to be manufactured at fairly uniform heights. The National Traffic and Motor Vehicle Safety Act (Pub. L. 89-563), as recently amended (Pub. L. 93-492), prohibits any manufacturer, distributor, dealer, or motor vehicle repair business from knowingly rendering inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable motor vehicle safety standard (@ 108(a) (2) (A)). Therefore, if the bumper were raised by one of the above classes of persons causing it no longer to comply with the Standard No. 215 requirements, a violation of the Act would have occurred. That law does not, however, prohibit an individual from altering the bumper on his own car. The National Highway Traffic Safety Administration, the agency that administers the Traffic Safety Act, is not authorized by that Act to prohibit vehicles with raised bumpers from operating on the highways. Except for certain limited areas such as motor carriers in interstate commerce, the regulation of vehicles operating on the highways is within the authority of the States. |
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ID: nht75-1.49OpenDATE: 08/25/75 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Pirelli Tire Corporation TITLE: FMVSS INTERPRETATION TEXT: Please forgive the delay in responding to your letter of May 5, 1975, which inquired about the permissibility of iron-branding the letters "N.A." on the sidewall of certain passenger car tires to indicate that they are not adjustable under your warranty. Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires -- Passenger Cars, specifies labeling and performance requirements for such tires. The NHTSA has no objection to the provision of additional labeling information such as the "N.A." which you have suggested. However, the tire must continue to be capable of meeting the standard's performance requirements at the completion of the hot-branding process. Sincerely, ATTACH. May 5, 1975 Office of Chief Counsel -- N.H.T.S.A. Att: Mark Schwimmer, attorney Sir: In reference to the phone conversation Friday morning, I am sending you a written request for the following information: We would like to know if there are some objections from your office to iron-brand N.A. (not adjustable) tires which may present possible vibrations, bleeding white sidewall, unbalance or which may not deliver the 40.000 mile guarantee even though they belong to a tire line which has the 40.000 mile guarantee. The tires involved (which are approximately 5000 units) will be sold at a discount of about 50%. Of course such tires have all the safety guarantee as the regular premium ones. Your prompt attention to this matter will be greatly appreciated. Sincerely, PIRELLI TIRE CORPORATION -- G. Buzzi-Ferraris, Technical Manager
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ID: nht67-1.23OpenDATE: 08/10/67 FROM: AUTHOR UNAVAILABLE; George C. Nield; NHTSA TO: Thermo King Corporation TITLE: FMVSS INTERPRETATION TEXT: Thank you for your letter of July 11, 1967, regarding the applicability of the Federal Motor Vehicle Safety Standards to accessories which are purchased for installation after procurement of the car and, in particular, Safety Standard No. 201. Standard No. 201, "Occupant Protection in Interior Impact -- Passenger Cars," applies only to vehicles as originally equipped and does not apply to accessories such as "after market" auto air conditioners. However, the public would certainly benefit from the maximum degree of conformance that may be feasible on after market installations. It is sincerely regretted that a written response to your first request was not received by you and trust that you were not inconvenienced. March 14, 1967 Dr. William Haddon Department of Commerce As manufacturers of "after market" auto air conditioners, the National Traffic and Motor Vehicle Safety Act as passed on January 23, 1967, is of concern to us. Does this Safety Act apply to manufacturers of accessories which are purchased by the car owner after he receives the car? The case in point is a car owner which purchases an "add-on" auto air conditioner; must this accessory comply with Standard 201? Recently one of our Engineers (Mr. D. Gregerson) contacted your office (Clayboure) and received verbal "no" answers to the above questions. Your aides mentioned that this could be confirmed by requesting it by letter. We would appreciate this confirmation when convenient for you. Very truly yours, L. L. Willis Vice President - Engineering
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ID: nht68-4.22OpenDATE: March 1, 1968 FROM: George C. Nield -- Acting Deputy Director, Motor Vehicle Safety Performance Service TO: Earl Allgaier -- Manager, Driver Education Division, Traffic Engineering and Safety Department, American Automobile Association TITLE: None ATTACHMT: Attached to letter from Joseph R. O'Gorman to A. Nathan Darby (Std. 101); Also attached to letter dated 3-14-91 from Paul Jackson Rice to George Smyth (A37; Std. 101); Also attached to letter dated 7-30-75 from Richard B. Dyson (signed by Z. Taylor Vinson) to Bryon A. Crampton; Also attached to letter dated 8-27-68 from Eugene B. Laskin to Barry G. Seitz (Std. 203; Std. 204) TEXT: Thank you for your letter of February 16 concerning the installation of dual controls and handicapped controls on passenger cars. In general, your evaluation of the effect of installing dual controls for driver training or controls for handicapped persons by dealers is correct. The present Federal motor vehicle safety standards do not prohibit the installation of these controls provided none of the requirements specified by the standards are eliminated or adversely affected by such installation. I am enclosing a complete set of standards now in effect for your information. In the event that dual steering controls and other controls are provided on driver training vehicles, the applicability of the appropriate standards is confined to the primary controls. For example, under Standard No. 101 the person seated behind the secondary steering control need not be able to reach all controls. Should you have any further questions on this matter, I would be most happy to have you again contact me. |
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ID: nht71-1.50OpenDATE: 01/29/71 FROM: AUTHOR UNAVAILABLE; C. H. Hartman for D. W. Toms; NHTSA TO: Morgan Motor Company, Ltd. TITLE: FMVSS INTERPRETATION TEXT: By letter of November 19, 1970, you petitioned for reconsideration of Federal Motor Vehicle Safety Standard No. 214 - Side Door Strength (35 F.R. 16801, October 30, 1970). After consideration of the issues raised by Morgan's petition, the National Highway Traffic Safety Administration has found no sufficient justification for amending the standard and the petition is therefore denied. Your company's petition states that the standard presents difficulties for cutaway doors, and that the structure of Morgan automobiles supplies a measure of protection through Clared side fenders that extend beneath the doors. The Administration recognizes that there is considerable variety in door and side structure. However, the need to protect occupants of all vehicles from injury in side collisions dictates a uniform measure of such protection, and the Administration has determined that the requirements of Standard No. 214 are reasonable, practicable and appropriate for passenger cars. The remaining points in your letter of November 19, 1970, are more nearly questions for interpretation than requests for reconsideration. Your second question pertains to the height (or length) of the loading device. The standard states only that the device must not contact any structure above the bottom edge of the door window opening. There is no other restriction on the maximum height of the test device, and it is not clear, without further explanation, why Morgan would be limited to a cylinder only 4 inches high. Your remaining question deals with the positioning of side windows. Although the standard specifies that side windows shall be in the uppermost position, it does not require that side windows exist and should not be so interpreted. |
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ID: nht71-5.5OpenDATE: 11/22/71 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Mr. James Eckstein TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of August 27, 1971, which was forwarded to this office October 20, 1971, by the Federal Trade Commission, regarding Government specifications for retreaded tires. You refer to problems you believe result from "out of roundness;" specifically, abnormal wear and blowouts at normal boulevard and highway speeds. You wish to determine whether this problem results from "too lenient" Government requirements, or whether "manufacturers are negligent." Out-of-roundness can occur in a retreaded tire for numerous reasons, and its presence does not necessarily indicate negligence on the part of the manufacturer. Moreover, while an out-of-round tire may affect vehicle handling it generally does not blow out at normal boulevard or even highway speeds, as a result of the out-of-round condition. Thus, a blow out in an out-of-round tire could have resulted from other factors. Many tire dealers, in addition, have machines that can eliminate out-of-roundness by cutting off excess tread. With reference to Federal regulations of retreaded tires, the first such regulation will become effective January 1, 1972. This regulation, Motor Vehicle Safety Standard No. 117, "Retreaded Pneumatic Tires," specifies size and performance requirements for retreaded tires for use on passenger cars. These requirements are similar to those that have been applicable to new passenger car tires since January 1, 1968. None of these requirements specifically concern "out-of-roundness." We do not have evidence that this characteristic, by itself, is a safety problem.
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ID: nht73-4.49OpenDATE: 08/15/73 FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA TO: Adams Rite Products, Inc. TITLE: FMVSS INTERPRETATION TEXT: This is in response to your July 25, 1973, request for copies of the Federal regulations concerning door locks and latches. Federal Standard 206, Door Locks and Door Retention Components, is enclosed. It regulates passenger cars, multipurpose passenger vehicles, and trucks. These categories include ambulances and "motor homes", which are self-propelled units with sleeping accommodations, generally constructed on a light truck chassis. Most other "mobile homes" are not self-propelled and they qualify as trailers, which are not subject to this standard. For your information, paragraph 9.1.2 of Ambulance Design Criteria has also been enclosed. This publication specifies the criteria which an ambulance must meet to qualify for Federal funding under the Highway Safety Program @ 402. ENCS. ADAMS RITE PRODUCTS, INC. July 25, 1973 Bureau of Motor Carrier Safety Federal Highway Administration Department of Transportation Washington, D. C. 20590 Adams Rite Products manufactures locks and latches used on commercial aircraft. We have been receiving many inquiries from mobile home builders and ambulance fabricators to supply latches that meet federal safety requirements. To date we have been unable to obtain copies of these regulations. Please forward two copies each of the regulations governing our type of equipment. If this is not under your jurisdiction, would you please forward this letter to the proper agency or notify us of the correct address. Robert B. Hirsch Marketing, Technical Staff |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.